1. Field of the Invention
This invention relates to a device useful for receiving, distributing and storing aliquots of a sample for testing or analysis and is particularly useful in the sampling techniques employed in clinical microbiology applications.
2. Description of Related Art
There are many analytical methods in chemistry, clinical chemistry and microbiology where a liquid sample is divided into more than one aliquot and then tested or examined. Even in the case of a single analytical protocol, there are many instances where replicate tests may be run on multiple aliquots of the sample to assure reproducibility of the result. When undergoing analysis and characterization, aliquots of a single sample may be reacted with either a variety of different chemical reagents for analytical purposes or may be reacted with differing amounts of a single reagent or both.
Many approaches exist to aid in the preparation of aliquots of a single sample. A common example of such a situation exists in the modern practice of clinical microbiology. An unidentified microorganism is routinely subjected to tests and procedures to determine its identity and/or pattern of resistance or susceptibility to destruction by a variety of antimicrobic chemicals. Commercial systems for such determination are provided by several manufacturers and typically use between 10 and 100 small aliquots of a sample suspension of the microorganism undergoing analysis. These systems require a variety of sterile vessels and pipetting aids for adequate filling when small physical amounts of aliquots are required. Therefore a need exists for a device and method for the preparation of sample aliquots that obviates the requirement for a variety of sterile vessels and pipetting aids.
A number of devices and containers are commercially available for the preparation of samples for analysis. For in vitro tests, disposable, multi-compartmental containers are provided by manufacturers in complete reagent kits. Immunoassays, which include the screening of blood samples for virus antibodies (e.g., the HIV or Hepatitis B virus), are commonly carried out in 96 well micro titration trays supplied precoated with appropriate reagents as part of a kit. Specialized equipment used in the preparation of samples for analysis is described in U.S. Pat. Nos. 4,761,378; 4,496,657; 4,493,896; 4,342,407; 3,826,717; 4,154,795 and 4,200,613.
Pipetting devices for inoculation of multi-compartmental containers include the SCEPTORPETTE.RTM. System (trademark of Becton Dickinson and Company) sold by Becton Dickinson Microbiology Systems, Towson, Md. and the device illustrated in U.S. Pat. No. 4,532,805.
In clinical microbiology, there are a number of devices and containers available, having a plurality of small reaction chambers. Such devices include the SCEPTOR.RTM. Bacterial MIC and ID testing system (trademark of Becton Dickinson and Company) sold by Becton Dickinson Diagnostic Instrument Systems, Towson, Md., MINITEK.TM. Systems (trademark of Becton Dickinson and Company) sold by Becton Dickinson Microbiology Systems, Cockeysville, Md. and the API20E.RTM. Identification Strip (trademark of Sherwood Medical) sold by Analytab Products, Division of Sherwood Medical, Plainview, N.Y.
Devices for manipulating liquid samples containing microorganisms for use with multi-welled containers are described in U.S. Pat. Nos. 4,548,245; 4,565,100; 4,239,853; 4,235,971; and 4,076,592.
Automated devices for microorganism identification and drug susceptibility testing include the commercially available VITEK.TM. system (trademark of Vitek Systems, Inc.) sold by Vitek Systems, Inc., Hazelwood, Mo. and the devices illustrated in U.S. Pat. Nos. 3,957,583; 4,018,652; 4,116,775 and 4,207,394.
U.S. Pat. No. 4,806,316 to Johnson, et. al. describes a device for use in exposing a sample to be tested to one or more test reactants. The Johnson et al. device comprises a docking port, a filling manifold, a vent control system and a filling channel. A specific feature of the device is that it uses complex flow paths for liquid and air.
A device comprising a planar surface with projections which align with the wells of a standard-type 96 well tissue culture plate is known in the art as shown in U.S. Pat. No. 4,483,925 to Noack. The projections used in Noack are of an absorbent nature and are used to control the removal of liquid from the wells.
A commercially available system, the F.A.S.T..TM. Immunoassay System (trademark of Becton Dickinson and Company) by Becton Dickinson Labware Products, Lincoln Park, N.J., provides simultaneous addition of a reagent to wells of a microtiter plate, however, each well of the microtiter plate is previously filled by pipetting steps.
Although there are a number of testing devices and pipetting systems available, there is no self-contained system available to produce small aliquots of a sample without entrapment of air bubbles.
The available devices also do not allow easy error-free reading of reaction results visually or by instruments for accurate test results, particularly when covered. The available devices do not have the means to provide aliquots of predetermined volume in a single operation and are not able to conveniently or accurately introduce reagents or materials into each separate aliquot for analysis thereof.
Thus, a special need exists for a device and method for the convenient preparation of separate aliquots into efficient areas without entrapment of air that obviates the requirement for a variety of sterile vessels, pipetting aids and multiple manipulations.